Pregnancy tests are readily available at drug stores or through your doctor’s office, but just how accurate is a pregnancy test?
Types of pregnancy tests
Each type of pregnancy test is a reliable indicator, if used correctly. Common errors include using a test that has expired or not following the instructions. So, be sure to check the expiration date on the package and read all the directions and follow them as indicated.
How does a pregnancy test work?
When a fertilized egg attaches to the lining of a uterus, human chorionic gonadotropin (HCG) is produced. This hormone enters the bloodstream and is expelled through urine (pee). When you urinate on the stick in a home pregnancy test or the doctor checks your urine sample in the office, it will either be positive (you are pregnant) or negative (you are not pregnant).
Some home pregnancy tests state that they are accurate as early as the first day of a missed period but it is probably a good idea to wait at least a day or so before testing to be sure your results are correct. Ovulation may vary from month to month, even if you are very regular. The egg can therefore implant at different times. A good interval is about a week after a missed period.
HCG production increases quickly, usually doubling every two or three days. So, if you are a bit patient, you will get a more accurate reading. If the test is positive, you should follow up with a medical professional for a second test of urine and/or blood work. This professional lab work will be able to determine the level or amount of HCG and provide a closer due date.
How to take a pregnancy test
Most home pregnancy tests tell you to place the end of the stick in the urine stream or to dip the stick into a container that has collected the urine. Instructions usually give you a timeframe about how long to wait before checking the results, which is generally two minutes or more.
Most tests have an indicator, like a line or symbol, to show that the test is working. If you don’t see that control indicator, the test is not performing correctly. You should likely take another test.
Some tests are more sensitive to the amount of HCG than others. This is another reason to wait a day or so before taking the test to confirm the results more accurately.
The ultimate results are shown as either a plus or minus sign, or the words “pregnant” or “not pregnant”.
There are some medications or fertility treatments that contain HCG and can affect the read out. However, generally antibiotics and birth control pills do not affect the accuracy.
Yes, it is possible to get a false positive result. This could be if you take the test too soon after starting fertility treatments, menopause, or problems in the ovaries.
Negative results can also be incorrect if you take the test too early in the pregnancy and the test is unable to detect the HCG.
Be sure to wait the allotted time to check the results; set a timer. It is also best to take the test the first thing in the morning because your urine will be more concentrated.
We discuss products we think are useful to people. If you buy something through our links, we may earn a commission. Remember to check with your personal physician to see if a product recommended is right for you.